1. Field of Invention
This invention relates generally to antiplaque mouth rinses conducive to oral hygiene, and more particularly to a mouth rinse whose formulation includes two antibacterial agents: Triclosan and cetyl pyridinium chloride. These coact to promote the delivery and retention of these agents on the teeth and soft tissue in the dental region of the oral cavity of the user to provide enhanced bacterial activity inhibiting the development of plaque.
2. Status of Prior Art
Dental plaque is a mucous film that harbors bacteria on the teeth. Calculus or tartar is an encrustation on the teeth consisting of salivary secretions, food residues and various salts, such as calcium phosphate. Dental plaque, a precursor of calculus, unlike calculus may form on any part of the tooth surface, including the gingival margin; hence it is implicated in the occurrence of gingivitis and periodontal disease.
It is generally acknowledged in dentistry that plaque which contains a combination of pathogenic microorganisms is a principal etiological factor associated with periodontal disease, dental infections and caries. The usual approach toward combating plaque is by mechanical expedients, such as toothbrushing, dental floss and toothpicks. However, even the most thorough tooth cleaning fails to eliminate interproximal plaque, yet it is the plaque lodging between adjacent teeth that plays a major role in periodontal disease. It therefore becomes necessary to complement mechanical oral hygiene measures with chemotherapeutic agents to inhibit the development of plaque.
Among the many chemotherapeutic agents heretofore used in inhibiting dental plaque are cationic agents such as chlorhexidine. However, there are major drawbacks associated with the use of this agent; for it not only has an unpleasant taste, but it also results in staining of the teeth and tongue.
Cethyl pyridinium chloride (CPC) is another cationic agent that has been formulated into various mouth rinse products. This antiseptic is usually used in a concentration ranging from 0.05 to 0.10% in mouth rinses. Yet as noted by Moran and Addy in J. Periodontol 1991; 62:562-562, "The Effects of a Cetylpyridinium Chloride Prebrushing Rinse as an Adjunct to Oral Hygiene and Gingival Health," there seems to be general agreement that CPC mouth rinses are effective but not as effective against plaque and gingivitis as chlorhexidine, although the use of CPC does not result in significant dental staining.
Also known to be effective against plaque is Triclosan, an antibacterial agent. In the article by Gjermo and Saxton, Antibacterial Dentifrices" appearing in J. Clin. Periodontal 1991: 18: 468-473, it is noted that several studies indicate that Triclosan alone, in spite of its broad antibacterial spectrum, has only a moderate effect on plaque formation. While Triclosan has been shown to be retained in plaque for several hours, the salivary release curve is relatively steep, thereby indicating a rapid release from oral binding sites. On the other hand, when Triclosan is incorporated in a copolymer which is retained on oral surfaces, it then provides the oral cavity with a reservoir of Triclosan. However, the copolymer makes no contribution to combating plaque.
As indicated in the Gaffar et al. U.S. Pat. No. 5,043,154, cationic antibacterial materials such as chlorhexidine and CPC have been the subject of many investigations as antibacterial agents. Nevertheless, in spite of the fact that these cationic agents have been used in conjunction with zinc salt acting as an anticalculus agent, they have not been found to be effective when used with anionic materials, such as a polyphosphate anticalculus agent.
In the oral composition disclosed in the Gaffar et al. U.S. Pat. No. 5,043,154, the mouth wash formulation includes a water-soluble polyphosphate salt as an anticalculus agent in combination with the water-insoluble noncationic antibacterial compound Triclosan, acting as an antiplaque agent. Triclosan is 2, 4, 4'-trichloro-2'-hydroxydiphenyl ether.
The antibacterial composition disclosed in the Nabi et al. U.S. Pat. Nos. 4,894,220 and 5,037,635 for use as a dentifrice or mouth wash contains water and includes Triclosan, a substantially water-insoluble noncationic antiplaque agent as well as a solubilizer therefor, such as propylene glycol. The formulation further includes a synthetic anionic linear polymeric polycarboxylate having a molecular weight of about 1000 to about 1,000,000. The anionic polymeric agent is said to enhance the delivery and retention of the antibacterial agent on teeth and on soft oral tissue. But this polymeric agent lacks antibacterial properties and does not itself act to retard the growth of plaque, even though it is retained in the dental region.
In the Gaffar et al. U.S. Pat. No. 5,037,637, there is disclosed an oral composition such as a mouth rinse containing a polyphosphate anticalculus agent and Triclosan, an antibacterial, antiplaque agent compatible therewith. The vehicle for these constituents is a water-alcohol mixture that includes a humectant. The total amount of water-alcohol in this preparation exceeds 70% by weight.
The Reed et al. U.S. Pat. No. 5,032,385 discloses an oral hygiene composition that includes Triclosan and polyethylene glycol. This patent points out that Triclosan, because of its lipophilic nature, tends to partition into a hydrophobic oil phase and a surfactant micellar phase and is therefore rendered unavailable for adsorption into the oral surfaces to be treated. By incorporating specified amounts of polyethylene glycol into the composition, the oral availability of the Triclosan can be maintained at an effective level.